It is known that the addition of Si-bonded hydrogen to an aliphatic multiple bond, which is frequently referred to as hydrosilylation, can be promoted by catalysts, and in particular platinum catalysts. Platinum catalysts are described, for example, in U.S. Pat. No. 3,814,730 to Karstedt, and in European Patent No. 0,032,377 to Lindner. The traditional and most widely used hydrosilylation catalyst is a solution of H.sub.1 PtCl.sub.6.6H.sub.2 O in 2-propanol, which solution contains the olefin complex H[(C.sub.3 H.sub.6)PtCl.sub.3 ] as the effective component and is called the Speier catalyst after its discoverer [cf. U.S. Pat. No. 2,823,218 to Speier, Dow Corning Corporation; issued on Feb. 11, 1958, and R. A. Benkeser, J. Kang, J. Organomet. Chem. 158 (1980) C9-C12].
Platinum complexes with alicyclic dienes, such as norbornadiene-, 1,5-cyclooctadiene- and dicyclopentadiene-platinum dichloride have also been described in a Japanese Published Application 79/76 529 (Shin-Etsu Chemical Industry Co., Ltd.); Japanese Published Application 79/76 530 (Shin-Etsu Chemica Industry Co.); and U.S. Pat. No. 4,276,252 (G. Kreis, Wacker-Chemie GmbH). Even though the abovementioned platinum-catalyzed hydrosilylation processes generally give good results, they are in most cases expensive due to the large number of parts by weight of metallic platinum required to achieve the desired hydrosilylation rate.
Therefore, it is an object of the present invention to provide stable platinum complexes which are superior to the catalyst systems known heretofore in their activity and are readily meterable and can be prepared easily and in high yield. A further object of the present invention is to provide platinum complexes which are suitable for the addition reaction of monomeric or polymeric silicon compounds having Si-bonded hydrogen with monomeric or polymeric compounds having an aliphatic multiple bond.